When it is raining really hard and is supposed to rain all day, I should take 2 pair of shoes with me.  I usually take 2 raincoats so one can dry off while I'm wearing the other one but 2 pair of shoes would be great when the first pair get too muddy to wear until I can wash them off!  I am thankful for croc-type boots and whatever that material is that keeps my feet dry. :)